My gti 1998 i want to no if i can uprate the injectors if so which ones? I have de-cat which makes it alot more responsive but still feels sluggish and will be also puttin a induction Kit on too. Any ideas or tips anyone plz? Thanks bill

Why do you want to change the injectors?
What other mods have you got?
The first things you want to do is a good panel filter, de-cat, full stainless exhaust system, four branch manifold and then a chip.
I wouldn't even think about changing injectors until your up to around 200-220bhp which will require a serious amount of engine work.
If you want to go crazy you could always go to Area Six and have one of their 300bhp packages which will cost over £5000 plus fitting

Hi thanks for replying i already have full stainless and de-cat but not manifold i want to up the bhp but don't have 5g lol is a palel filter better than a cone? After chip and manifold what next? I dint even no what the gti bhp is standard? It just feels so sluggish feel she has alot more to give? Thanks bill

A gti shouldn't be sluggish, especially with a decat and stainless cat-back if that's what you have, unless maybe the exhaust is an inefficient design... or perhaps you have a different perception of sluggish than I do lol

I'd check out some more basic stuff before doing any further mods if I were you, numerous things can affect performance on any car, perhaps you should start there, here's a few things off the top of my head

Brakes sticking? Get them checked out

Need a service? Use semi-synthetic 5w30 if you aren't already, worth changing the fuel filter in the tank, they can get dirty'n clogged over time and they're cheap to replace, same goes for old plugs etc

If you haven't already it's worth fitting a new timing kit especially as if you're modding for more power, aging parts almost certainly will fail sooner and it's always better to replace before failure as things like a timing belt snapping whilst you're driving at speed can cause anything from untold engine damage to an untimely death

The above stuff is basically saying, make sure everything else is right before you start modding for power or expect trouble, onto mods'n improvements

Check for too much slack in the throttle cable, I found an excessive ammount in both the gti and tddi escort, on the gti if you look to the left of the engine as you're looking at it from the front of the car you'll see a cable running from the throttle body (where the air filter pipe ends) which kinda bends back towards the driver's seat

You'll see a ridged rubber sleeve on the cable and behind it (the side of the sleeve closest to the interior of the car) is a U-shaped clip which holds the cable in place, the clip fits into ridges on another sleeve that's actually fixed to the cable. Pull the clip off and you can then adjust the tension of the cable by pulling the cable towards the front of the car to take slack out, push towards the interior to increase the slack.

When you're satisfied put the clip back into place making sure it's slotted into the ridges on the cable

Be aware there should be a little slack to allow for movement whilst driving, if it's too tight the car will tick over higher and/or occasionally rev higher suddenly whilst in situations like going over bumps. Taking out the excessive slack made a considerable difference to both my petrol and diesel escorts.

Some people say fitting a 2.0 mondeo throttle body is an improvement but I believe that's a myth as the barrel is exactly the same diameter as the 1.8 body so logic says it can't physically push any more air through, the 2.0l one just has a bigger cam for the cable to fit on which means for every centimetre you push the pedal down the throttle opens 'wider' ... but it can still only open as wide as it can open so you'd find you can't push the pedal down as far, physically it can't make a difference to the true performance of the car. May feel nicer to some people, too sensitive to others so it's just personal preference to the 'feel' that ya like

A more sensible thing to do in my opinion is to smooth out and polish the barrel (inside) of your throttle body, I used wet'n dry to smooth it all off then used some metal polish on superfine wire wool, starts off as a grainy surface and ends up almost like a mirror that allows air to flow in a bit quicker. Costs a few quid for wet'n dry, good quality superfine wire wool and some metal polish (which you'll use again in a minute) and some elbow grease, not a massively noticeable gain but every litte effiecieny improvement you make is cumulative .. it all adds up!

On the subject of airflow which is like really important if you want power, the quicker and colder you can send air in the more the ecu will adjust and send in more fuel to compensate, which is lovely if you got the time and money to fit a nice turbo & intercooler but as you don't wanna spend too much improve the airflow you already got and remember cooler is better

Some people will recommend panel filters, some cones, some will say 'I just drilled holes in my airbox', in other words it comes down to personal preference but I had great results on the gti with a quikshift stainless mesh cone filter, although I didn't just take off the airbox and fit the cone on the end, that would be worse than using the stock filter, but it's surprising just how many people do that

The reason is because then you have a totally exposed filter sucking in all the hot air that comes off the exhaust manifold and engine block that rises to the top of the engine bay, which is really bad for your engine and will definitely decrease performance whereas the stock escort air filter design is actually pretty good because it uses what's called a ram pipe, fitted to the front of the car sucking air in through the top grille into the bottom of the filter box, up through the filter along the pipe into the throttle body

A panel filter is basically a less restictive replacement for the oem paper filter inside the filter box so it's still using the ram pipe setup, much better than just sticking a cone on the end of pipe. You have to oil these filters, forget the logic why, but I don't see oil as an ideal medium to pass air through quickly

To make a cone filter work properly you can't just stick it onto the end of gti maf, you need to get the cone sitting a couple of inches away from the ram pipe at a position where the pipe is blowing cold air straight onto the middle of the filter, the ram pipe is excellent for feeding cold air into the engine bay but your filter makes best use of it when placed directly next to it, the small gap allows the cold air to spread over the filter's surface

The filter is then sitting lower down avoiding all that heat collecting at the top of the engine bay, add a polished heat-shield angled slightly towards the exhaust manifold and you have an effiicient filter sucking in some quickly delivered cold air, you just have to take as much of that hot air outta the mix as possible or it's pointless

Use whatever silicon elbows and stainless pipe you need coming off the maf to place the filter at whatever you decide is the optimum position, or if you wanna spend a bit more but do a better job of it, do away with the stock air-pipe and make a stainless one

Whatever you do filter-wise it's a good a time as any to polish out the maf in much the same way as with the throttle body, main difference here is being careful not to damage the sensor wires, there's a plate inside the barrel of the maf covering them you might be tempted to take off while polishing, DO NOT! The sensor wires are under it, give these a careful clean after you're done polishing with some electrical contact cleaner

(The maf btw is the master airflow sensor, metal gizmo on the air-pipe with an electrical connector going into it and do not get conned into replacing with a 2.0l one, they're identical)

Stock injectors are good for up to around 156bhp, if you need more then 2.0 mk1 (not sure about the mk2) mondeo injectors are a straight swap and good for a fair bit more but I'm not sure exactly how much

Another straight swap off the same mondeo is the cams, the difference between the 1.8 113bhp zetec and the 130 I'm given to understand is the cams, the 130 1.8 has the same cams as the 130 2.0l, so that'll give perhaps a bit over 20bhp but will slightly decrease acceleration .... and watch your fuel gauge if you floor it!

Porting and polishing the head inlets & outlets is something you may be able to do yourself which is again the same principle as polishing the throttle body & maf, namely making for a less restrictive air & fuel flow (though the outlets are for the same reason as you use a decat and stainless exhaust). But I can't stress enough, don't just go trying it it, if you don't have a source of some fairly expert advice/oversight, it's not really a diy job

A head-skim can give a small power increase and some shopping around can get it done for as little as £30

Stock bhp according to ford for the gti is 113, not many cars are pushing out exactly what your manual says though, especially an older car like an escort which you already said is running sluggish so what you'd end up with isn't a set-in-stone figure, but don't just think about bhp anyway, for acceleration & pulling power, sheer grunt, torque is equally if not more important

Remap, doing one when you're planning future mods is not good planning, values change with mods so it makes sense to make all your physical changes and remap last, imagine how off your remap would be if you decided after getting it done to fit a turbo, you'd have to get it remapped again to see full benefit

But don't ignore the ecu when you're changing things, every mod changes values so the ecu has to compensate and it does it best (especially if you've changed a few things) when the ecu has been reset, resetting the ecu is a bit like restoring your computer. After a reset it sorta sets about learning how best to set things according to readings it's getting from all the various sensors and adapts to your mods & driving style

Resetting the ecu isn't a complex process, all you need is .... a 10mm spanner, disconnect the battery for a few hours, you know it's worked when you lost all your radio stations you set up, I usually just leave it disconnected overnight, connect the battery back up, start the car and let it tick over

Wait until it's ticking over at the normal rpm (900 on the gti), wait another five minutes, take it for a longish drive, at least fifty miles, and if possible take a route where you can safely drive it hard, observing speed limits of course ;p

Oh, on the sluggish thing, my gti (estate) with just the basic stuff put right, full service, new timing, clutch, etc, aftermarket (smaller & less restrcitive) cat, renewed exhaust but with oem steel,fitted cone filter polished out maf & throttle body, re-tensioned throttle cable, two and a half mile mountain road where I live it'll pull 85 at best in third (I read somewhere they can do 115 in 4th but I ain't convinced), but I can in two spots coast comfortable in 5th at 60 on about 2400rpm, it's pretty bendy and averages about a 65-70 gradient

At 5000rpm in 5th it's pulling 120mph (unless the gauge is off), it'll rev higher but I've always run out of road or balls to find out just how much, might be useful as a comparison on whether yours really is sluggish

Anyone wanting to port & polish their head inlet & outlet manifolds ... be careful and read up on it first!

There's basically three things that MUST be avoided, these are:

At all costs avoid making any contact whatsoever with the valves whether it be your dremmel/drill grinding/sanding bit, wet'n dry, wire wool, or pretty much anything else you can think of, when I did mine I took the valves out, did the port & polish, refitted the valves and re-lapped them at the same time. Re-seating your valves on any older engine is worth thinking about doing, plenty of how-to vids on youtube

Do not polish the inlets to a mirror finish, exhaust yes, inlets NO NO NO!

DO not open inlets or exhaust wider than your inlet and outlet manifold gaskets

A simple run-down of what you SHOULD do:

Get new inlet & outlet manifold gaskets, offer them up to your head in the same fashion as if you were actuallly fitting them, fix them in place with a nut/bolt or two. You will then see that the inlets/exhausts openings are usually a fair bit smaller than the gaskets and they can be opened out to fit the gasket, basically making them bigger openings allowing a more free flow of air, fuel and exhaust gases. I've seen allsorts of things suggested to mark up what you can take off, a permanent marker worked for me

Inlets, start off with a grinding attachment (I used dremmel bits and a drill, dremmel's not powerful enough if you don't have forever), working in a circular motion as opposed to an 'in-and-out' motion until you've opened the ports out almost to where you marked with your gasket, then use a sanding attachment in a circular motion to take it the rest of the way. You're not looking to make the inlets perfectly smooth as this would prevent air & fuel from mixing properly, think in terms of opening out and making less restrictive rather than making things completely smooth when working on the inlets

Exhausts, start off by doing pretty much the same as you did with the inlets, except this time you don't have to worry about mixing, the more you 'flatten off' and open out these (within reason) the better, after using the dremmel grinder and sanding attachments I used the following to continue smoothing out until I had a mirror finish:

While it's all off there's no better time to clean up and paint or polish your rocker cover to make things look a lot nicer under the hood, and everyone knows that anything making things look nicer gives you masses more bhp!

As it turns out I also have a gti escort (estate like my diesel, dogs won't let me have anything else!) that I've had off the road for a spell following a disaster caused by lending it to my sister, porting and polishing the head is one of the things I've done while it's not been getting used so as yet I don't really know for sure how much difference it's made, and even after it's mot'd and back on the road next week I won't know because I've done a few other things including fitting the 130 bhp 2l cams